Medical grafting methods and apparatus

ABSTRACT

Methods and apparatus for delivering and installing a new length of tubing between two sections of a patient&#39;s existing body organ tubing and at least partly outside of that existing structure. For example, the new length of tubing may be for the purpose of providing the patient with a coronary bypass. The new tubing may be an artificial graft, a natural graft (harvested elsewhere from the patient), or both. The new tubing is delivered to and installed at the operative site primarily by working through the patient&#39;s existing tubular body organ structure. This avoids the need for any significant surgery on the patient. The artificial grafts may have shapes other than tubular. Certain procedural and apparatus aspects of the invention have uses other than in connection with grafting in general or tubular grafting in particular.

[0001] This application is a continuation of U.S. patent application No.09/955,244, filed Sep. 17, 2001, which was a continuation of U.S. patentapplication No. 09/323,181, filed May 28, 1999 (now U.S. Pat. No.6,302,905), which was a continuation of U.S. patent application No.08/745,618, filed Nov. 7, 1996 (now U.S. Pat. No. 5,976,178). All threeof these prior applications are hereby incorporated by reference hereinin their entireties.

BACKGROUND OF THE INVENTION

[0002] This invention relates to grafts for use in the repair,replacement, or supplement of a medical patient's natural body organstructures or tissues. The invention also relates to methods for makinggraft structures. The invention further relates to methods and apparatusfor delivering a graft to an operative site in a patient, and forinstalling the graft at that site. Some aspects of the invention mayhave other uses such as for viewing the interior of a patient, providingaccess to the interior of a patient for other procedures, etc. Anexample of the possible uses of the invention is a minimally invasivecardiac bypass procedure. This example will be considered in detail, butit will be understood that various aspects of the invention have manyother possible uses.

[0003] Several procedures are known for revascularizing the human heartin order to treat a patient with one or more occluded coronary arteries.The earliest of these procedures to be developed involves exposing theheart by means of a midline sternotomy. Following surgical exposure ofthe heart, the patient's aorta and vena cava are connected to aheart/lung machine to sustain vital functions during the procedure. Thebeating of the heart is stopped to facilitate performance of theprocedure. Typically, a suitable blood vessel such as a length of thepatient's saphenous (leg) vein is harvested for use as a graft. Thegraft is used to create a new, uninterrupted channel between a bloodsource, such as the aorta, and the occluded coronary artery or arteriesdownstream from the arterial occlusion or occlusions.

[0004] A variation of the above procedure involves relocating a mammaryartery of the patient to a coronary artery.

[0005] Although the above-described sternotomy procedures areincreasingly successful, the high degree of invasiveness of theseprocedures and the requirement of these procedures for generalanesthesia are significant disadvantages. Indeed, these disadvantagespreclude use of sternotomy procedures on many patients.

[0006] More recently, less invasive procedures have been developed forrevascularizing the heart. An example of these procedures is known asthoracostomy, which involves surgical creation of ports in the patient'schest to obtain access to the thoracic cavity. Specially designedinstruments are inserted through the ports to allow the surgeon torevascularize the heart without the trauma of a midline sternotomy.Drugs may be administered to the patient to slow the heart during theprocedure. Some thoracostomy procedures involve relocating a mammaryartery to a coronary artery to provide a bypass around an occlusion inthe coronary artery.

[0007] Thoracostomy bypass procedures are less traumatic than sternotomybypass procedures, but they are still too traumatic for some patients.Also, the number of required bypasses may exceed the number of mammaryarteries, thereby rendering thoracostomy procedures inadequate to fullytreat many patients.

[0008] Another technique for revascularizing the human heart involvesgaining access to the thoracic cavity by making incisions between thepatient's ribs. This procedure is known as thoracotomy. It is alsosubstantially less traumatic than midline sternotomy, but it is stilltoo traumatic for some patients.

[0009] In view of the foregoing, it is an object of this invention toprovide less traumatic methods and apparatus for revascularizing apatient.

[0010] It is another object of the invention to provide minimallyinvasive methods and apparatus for repairing, replacing, orsupplementing the blood vessels or other body organ tubing or tissues ofa patient.

[0011] It is still another object of the invention to provide improvedgraft structures for use in the repair, replacement, or supplementing ofnatural body organ structures or tissues, and to provide methods formaking such graft structures.

[0012] It is yet another object of the invention to provide improvedmethods and apparatus for transporting or delivering and installinggraft structures for use in the repair, replacement, or supplementing ofnatural body organ structures or tissues of a patient.

SUMMARY OF THE INVENTION

[0013] These and other objects of the invention are accomplished inaccordance with the principles of the invention by providing methods andapparatus for substantially non-surgically installing a new length oftubing in a patient between two sections of the patient's existing bodyorgan tubing, the new length of tubing being delivered to the operativesite by passing along existing tubing, but installed at the operativesite so that it is at least partly outside the existing tubing. (As usedherein, references to a patient's existing body organ tubing or the likeinclude both natural and previously installed graft tubing (whethernatural, artificial, or both). A previous installation of graft tubingmay have occurred in a previous procedure or earlier in a current andon-going procedure. References to a length of tubing also include plurallengths of tubing.) At one end of the operative site, the new length oftubing is caused to extend out through an opening made in the existingtubing. The outwardly extending end portion of the new tubing is guidedto the other end of the operative site. At that other end anotheropening is made in the existing tubing and the extending end portion ofthe new tubing is attached to the existing tubing via that opening. Theother end portion of the new tubing (remote from the extending portion)is similarly attached to the existing tubing at the first-describedopening. The new tubing installation is now complete, and the apparatusused to make the installation can be withdrawn from the patient.

[0014] In the most preferred embodiment, all or substantially allnecessary apparatus is inserted into the patient via the patient'sexisting body organ tubing. In addition, all or substantially allapparatus functions at the operative site are remotely controlled by thephysician (a term used herein to also include supporting technicians)from outside the patient's body.

[0015] Preferred apparatus in accordance with the invention includes afirst elongated instrument for extending through the patient's existingbody organ tubing to a first end of the operative site, and a secondelongated instrument for similarly extending through the patient'sexisting tubing to a second end of the operative site. Each instrumentincludes a structure capable of penetrating the existing tubing at theassociated end of the operative site. In addition, these structures arecapable of interengaging with one another outside the existing tubing toprovide a substantially continuous structural path from outside thepatient, along the patient's existing tubing, and then outside thattubing from one end to the other of the operative site. This structureis used to guide the new length of tubing into the patient and intoposition at the operative site.

[0016] At least one of the elongated instruments preferably includesmechanisms for fastening each end portion of the new length of tubing tothe adjacent existing body organ tubing. For example, these mechanismsmay activate fasteners on or associated with the new tubing.

[0017] The new tubing may be artificial graft tubing. Alternatively, thenew tubing may be natural body organ tubing (e.g., tubing harvested fromanother location in the patient's body). As still another alternative,the new tubing may be a combination of artificial and natural tubing(e.g., natural tubing disposed substantially concentrically insideartificial tubing).

[0018] A preferred form of artificial tubing includes a tube frame of afirst highly elastic material (such as nitinol) covered with a secondhighly elastic material (such as silicone rubber) to substantially fillin the apertures in the frame. This combination produces an artificialgraft that is distensible like natural body organ tubing such as anatural artery. The covering on the frame is preferably made porous to apredetermined degree to improve its bio-utility in this context. Apreferred method of providing such porosity is to make the covering froman elastic material that is mixed with particles of a material that canbe removed (e.g., by vaporization) after the covering has been appliedto the mesh. When the particles are removed, voids are left in thecovering that give it the desired porosity.

[0019] The artificial grafts of this invention may be coated (in thecase of tubular grafts, on the inside and/or outside) to still furtherenhance their bio-utility. Examples of suitable coatings are medicatedcoatings, hydrophylic coatings, smoothing coatings, collagen coatings,human cell seeding coatings, etc. The above-described preferred porosityof the graft covering helps the graft to retain these coatings.Additional advantages of the artificial grafts of this invention aretheir elasticity and distensibility (mentioned above), their ability tobe deployed through tubes of smaller diameter (after which theyautomatically return to their full diameter), the possibility of makingthem modular, their ability to accept natural body organ tubingconcentrically inside themselves, their ability to support developmentof an endothelial layer, their compatibility with MRI procedures, theirability to be made fluoroscopically visible, etc.

[0020] Although grafts in the form of tubing are described above,certain aspects of the invention are equally applicable to other graftprocedures and to grafts having other shapes.

[0021] Further features of the invention, its nature and variousadvantages will be more apparent from the accompanying drawings and thefollowing detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a simplified longitudinal sectional view showing aportion of an illustrative procedure and related apparatus in accordancewith this invention.

[0023]FIG. 2 is a simplified longitudinal sectional view showing aportion of a more particular illustrative procedure and relatedapparatus in accordance with the invention.

[0024]FIG. 3 is a simplified longitudinal sectional view showing anillustrative embodiment of a portion of the FIG. 2 apparatus in moredetail.

[0025]FIG. 3a is a view similar to FIG. 3 showing an alternativeillustrative embodiment of the FIG. 3 apparatus.

[0026]FIG. 4 is a simplified elevational view showing an illustrativeembodiment of a portion of the FIG. 3 apparatus in still more detail.

[0027]FIG. 5 is a simplified longitudinal sectional view showing anotherportion of an illustrative procedure and related apparatus in accordancewith this invention.

[0028]FIG. 6 is a view similar to FIG. 2 showing a later stage in theillustrative procedure depicted in part by FIG. 2, together with relatedapparatus, all in accordance with this invention.

[0029]FIG. 7a is a simplified longitudinal sectional view of anillustrative embodiment of a portion of the FIG. 6 apparatus in moredetail.

[0030]FIG. 7b is a simplified elevational view of a portion of the FIG.7a apparatus, but with the depicted elements in a different physicalrelationship to one another.

[0031]FIG. 7c is a simplified longitudinal sectional view of analternative embodiment of one component of the FIG. 7a apparatus.

[0032]FIG. 7d is a simplified longitudinal sectional view of analternative embodiment of another component of the FIG. 7a apparatus.

[0033]FIG. 7e is a simplified elevational view of another alternativeembodiment of the component shown in FIG. 7d.

[0034]FIG. 7f is a simplified elevational view of an alternativeembodiment of still another component shown in FIG. 7a.

[0035]FIG. 7g is a simplified elevational view of an alternativeembodiment of yet another component shown in FIG. 7a.

[0036]FIG. 8 is a simplified longitudinal sectional view similar to aportion of FIG. 6 showing a still later stage in the illustrativeprocedure depicted in part by FIG. 6.

[0037]FIG. 8a is a simplified sectional view of the apparatus shown inFIG. 8 without the associated tissue structure being present.

[0038]FIG. 9 is a simplified cross sectional view of an illustrativeembodiment of further illustrative apparatus in accordance with thisinvention.

[0039]FIG. 10 is a simplified longitudinal sectional view of anillustrative embodiment of a portion of the FIG. 9 apparatus.

[0040]FIG. 10a is a view similar to FIG. 10 showing a possiblealternative construction of the FIG. 10 apparatus.

[0041]FIG. 10b is another view similar to FIG. 10 showing anotherpossible alternative construction of the FIG. 10 apparatus.

[0042]FIG. 10c is another view similar to FIG. 10 showing still anotherpossible alternative construction of the FIG. 10 apparatus.

[0043]FIG. 11 is a view similar to FIG. 6 showing an even later stage inthe illustrative procedure depicted in part by FIG. 8, together withrelated apparatus, all in accordance with this invention.

[0044]FIG. 12 is a view similar to a portion of FIG. 11, but in somewhatmore detail, showing a still later stage in the illustrative proceduredepicted in part by FIG. 11.

[0045]FIG. 12a is a view similar to FIG. 12 showing a possiblealternative construction of the FIG. 12 apparatus.

[0046]FIG. 13 is a view similar to FIG. 12 showing an even later stagein the illustrative procedure depicted in part by FIG. 12.

[0047]FIG. 14 is a view similar to FIG. 11 showing a still later stagein the illustrative procedure depicted in part by FIG. 13.

[0048]FIG. 15 is a simplified longitudinal sectional view of anillustrative embodiment of a portion of still further illustrativeapparatus in accordance with this invention.

[0049]FIG. 15a is a simplified elevational view of a structure which canbe used to provide part of the apparatus shown in FIG. 15.

[0050]FIG. 15b is a view similar to FIG. 15a showing more of thestructure of which FIG. 15a is a part.

[0051]FIG. 15c is a view similar to FIG. 15b showing the FIG. 15bstructure in another operational condition.

[0052]FIG. 15d is a simplified elevational view of an alternativestructure which can be used to provide part of the apparatus shown inFIG. 15.

[0053]FIG. 15e is a view similar to FIG. 15d showing the FIG. 15dstructure in another operational condition.

[0054]FIG. 15f is a simplified longitudinal sectional view of anotheralternative structure which can be used to provide part of the apparatusshown in FIG. 15.

[0055]FIG. 15g is a view similar to FIG. 15f showing the FIG. 15fstructure in another operational condition.

[0056]FIG. 16 is a simplified elevational view of an illustrativeembodiment of one component of the FIG. 15 apparatus.

[0057]FIG. 17 is a simplified longitudinal sectional view of anillustrative embodiment of another portion of the FIG. 15 apparatus.

[0058]FIG. 18 is a view similar to a portion of FIG. 14 showing an evenlater stage in the illustrative procedure depicted in part by FIG. 14.

[0059]FIG. 19 is a view similar to FIG. 18 showing a still later stagein the FIG. 18 procedure.

[0060]FIG. 20 is a view similar to FIG. 19 showing an even later stagein the FIG. 19 procedure.

[0061]FIG. 21 is a view similar to another portion of FIG. 14 showing astill later stage in the FIG. 20 procedure.

[0062]FIG. 22 is a view similar to FIG. 21 showing an even later stagein the FIG. 21 procedure.

[0063]FIG. 22a is a view similar to FIG. 22 showing a still later stagein the FIG. 22 procedure.

[0064]FIG. 22b is a view similar to FIG. 22a showing an even later stagein the FIG. 22a procedure.

[0065]FIG. 23 is a view similar to FIG. 22b showing a still later stagein the FIG. 22b procedure.

[0066]FIG. 24 is a view similar to FIG. 23 showing an even later stagein the FIG. 23 procedure.

[0067]FIG. 25 is a simplified longitudinal sectional view of anillustrative embodiment of a portion of more apparatus in accordancewith this invention.

[0068]FIG. 26 is a view similar to FIG. 20 showing a later stage in theFIG. 24 procedure.

[0069]FIG. 27 is a view similar to FIG. 26 showing a still later stagein the FIG. 26 procedure.

[0070]FIG. 28 is a view similar to FIG. 24 showing an even later stagein the FIG. 27 procedure.

[0071]FIG. 29 is a view similar to FIG. 28 showing a still later stagein the FIG. 28 procedure.

[0072]FIG. 30 is a view similar to FIG. 29 showing an even later stagein the FIG. 29 procedure.

[0073]FIG. 31 is a view similar to FIG. 14 showing the end result of theprocedure depicted in part by FIG. 30.

[0074]FIG. 32 is a simplified longitudinal sectional view showing an endresult similar to FIG. 31 but in a different context.

[0075]FIG. 33 is a simplified longitudinal sectional view showing apossible alternative construction of portions of the apparatus showingin FIG. 15.

[0076]FIG. 34 is a simplified elevational view (partly in section)showing another possible alternative construction of portions of theFIG. 15 apparatus.

[0077]FIG. 35 is a simplified longitudinal sectional view of the FIG. 34apparatus in another operating condition.

[0078]FIG. 36 is a simplified elevational view of apparatus which can beused as an alternative to certain apparatus components shown in FIGS. 15and 17.

[0079]FIG. 37 is a simplified elevational view (partly in section)showing additional components with the FIG. 36 apparatus.

[0080]FIG. 38 is a simplified longitudinal sectional view showing stillanother possible alternative construction of portions of the FIG. 15apparatus.

[0081]FIG. 39 is a simplified elevational view showing in more detail apossible construction of a portion of the FIG. 38 apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] Because the present invention has a number of differentapplications, each of which may warrant some modifications of suchparameters as instrument size and shape, it is believed best to describecertain aspects of the invention with reference to relatively genericschematic drawings. To keep the discussion from becoming too abstract,however, and as an aid to better comprehension and appreciation of theinvention, references will frequently be made to specific uses of theinvention. Most often these references will be to use of the inventionto provide a bypass around an occlusion or obstruction (genericallyreferred to as a narrowing) in a patient's coronary artery, and inparticular a bypass from the aorta to a point along the coronary arterywhich is downstream from the coronary artery narrowing. It is emphasizedagain, however, that this is only one of many possible applications ofthe invention.

[0083] Assuming that the invention is to be used to provide a bypassfrom the aorta around a coronary artery narrowing, the procedure maybegin by inserting an elongated instrument into the patient'scirculatory system so that a distal portion of the instrument extendsthrough the coronary artery narrowing to the vicinity of the point alongthe artery at which it is desired to make the bypass connection. This isillustrated by FIG. 1 which shows elongated instrument 100 entering thepatient's circulatory system 10 at a remote location 12 and passingcoaxially along vessels in the circulatory system until its distal endportion 104 passes through narrowing 22 in coronary artery 20 andreaches the downstream portion 24 of the artery to which it is desiredto make a bypass connection. For example, the entry location 12 ofinstrument 100 may be a femoral (leg) artery of the patient, a brachialartery of the patient, or any other suitable entry point. It will beappreciated, however, that entry point 12 is typically remote from thelocation at which the bypass is to be provided, and that control ofinstrument 100 throughout its use is from the proximal portion 102 thatis outside the patient at all times.

[0084] For the illustrative procedure being discussed, FIG. 2 shows apreferred embodiment of instrument 100 in more detail. As shown in FIG.2, instrument 100 may include a catheter tube 110 which is inserted(from location 12 in FIG. 1) via the patient's aorta 30 to the ostium ofcoronary artery 20. Another tubular structure 120 is then extended fromthe distal end of catheter 110, through narrowing 22 to location 24.

[0085] An illustrative construction of tubular structure 120 is shown inmore detail in FIG. 3. There it will be seen that structure 120 may havetwo lumens 130 and 140. Near the distal end of structure 120, lumen 130communicates with the interior of an inflatable balloon 132 on one sideof structure 120, while lumen 140 opens out to the opposite side ofstructure 120. Lumen 140 contains a longitudinal structure 150 which maybe a stylet wire with a sharpened distal tip 152 (see FIG. 4). (AlthoughFIG. 4 shows indentations behind tip 152, those indentations could beeliminated if desired.) Structure 120 may be provided with a distalspring tip 122 to help guide the distal end of structure 120 alongcoronary artery 20 and through narrowing 22. A safety ribbon 123 (e.g.,of the same material as tip 122) may be connected at its proximal end tothe distal end of member 120 and at its distal end to the distal end oftip 122 to improve the performance of tip 122 and to help preventseparation of any portion of tip 122 from structure 120 in the event ofdamage to tip 122. Structure 120 may have radiologic (e.g., radio-opaqueor fluoroscopically viewable) markers 124 at suitable locations to helpthe physician place the structure where desired in the patient's body.Catheter 110 may also have radiologic markers 112 for similar use.Balloon 132 is initially deflated. Longitudinal structure 150 isinitially retracted within lumen 140. However, the distal portion oflumen 140 is shaped (as indicated at 142 in FIG. 2) to help guide thedistal tip 152 of structure 150 out to the side of structure 120 whenstructure 150 is pushed distally relative to structure 120. This isdiscussed in more detail below. As earlier description suggests, each ofcomponents 110, 120, and 150 is separately controllable from outside thepatient, generally indicated as region 102 in FIG. 1.

[0086] As an alternative to providing balloon 132 as an integral part ofone structure 120, balloon 132 may be provided on another longitudinalstructure 120′ (FIG. 3a) which is substantially parallel to theremaining components described above for structure 120. Structure 120′may be substantially separate from structure 120, or it may be attachedto structure 120.

[0087] After instrument 100 is positioned as shown in FIGS. 1 and 2, asecond elongated instrument 200 is similarly introduced into thepatient's circulatory system 10 as shown generally in FIG. 5. Forexample, instrument 200 may enter the patient (at 14) via a femoralartery, a brachial artery, or any other suitable location, which againis typically remote from the bypass site. If one femoral artery is usedto receive instrument 100, the other femoral artery may be used toreceive instrument 200. Or the same femoral artery may be used toreceive both instruments. Or any other combination of entry points maybe used for the two instruments. Instrument 200 is inserted until itsdistal end is adjacent to the point 34 in the circulatory system whichit is desired to connect to point 24 via a bypass. This is illustratedin a more specific example in FIG. 6 where the distal end of instrument200 is shown at location 34 in aorta 30. The particular location 34chosen in FIG. 6 is only illustrative, and any other location alongaorta 30 may be selected instead. Radiologic markers 206 may be providedon the distal portion of instrument 200 to help the physician positionthe instrument where desired. Note that FIG. 6 shows portions ofinstruments 100 and 200 side by side in aorta 30.

[0088] An illustrative construction of instrument 200 is shown in moredetail in FIG. 7a. This FIG. shows the distal portions of elements 220,230, 240, and 250 telescoped out from one another and from the distalend of outer member 210 for greater clarity. It will be understood,however, that all of these elements are initially inside of one anotherand inside outer member 210. Indeed, member 210 may be initiallypositioned in the patient without any or all of elements 220, 230, 240,and 250 inside, and these elements may then be inserted into member 210.Moreover, the number of members like 220, 230, etc., may be more or lessthan the number shown in FIG. 7a, depending on the requirements of aparticular procedure.

[0089] Outer member 210 may be a catheter-type member. The distalportion of catheter 210 may carry two axially spaced annular balloons212 and 214. Proximal balloon 212 is inflatable and deflatable viainflation lumen 216 in catheter 210. Distal balloon 214 is inflatableand deflatable via inflation lumen 218 in catheter 210. Lumens 216 and218 are separate from one another so that balloons 212 and 214 can beseparately controlled. Balloons 212 and 214 are shown substantiallydeflated in FIG. 7a. The distal end of catheter 210 may be tapered asshown at 211 in FIG. 7c to facilitate passage of catheter 210 through anaperture in aorta 30 as will be described below.

[0090] Coaxially inside catheter 210 is tubular sheath member 220.Sheath 220 is longitudinally movable relative to catheter 210. Thedistal portion of sheath 220 may be tapered as shown at 222 in FIG. 7d,and/or externally threaded as shown at 224 in FIG. 7e. Either or both offeatures 222 and 224 may be provided to facilitate passage of sheath 220through an aperture in aorta 30 as will be described below. If threads224 are provided, then sheath 220 is rotatable (either alone or withother components) about the longitudinal axis of instrument 200 in orderto enable threads 224 to engage the tissue of the aorta wall and helppull sheath 220 through the aorta wall.

[0091] Coaxially inside sheath member 220 is power steering tube 230.Tube 230 is longitudinally movable relative to sheath 220. Tube 230 mayalso be rotatable (about the central longitudinal axis of instrument200) relative to sheath 220, and the distal end of tube 230 may bethreaded on the outside (as shown at 232 in FIG. 7f) for reasons similarto those for which threading 224 may be provided on sheath 220. Tube 230is preferably controllable from its proximal portion (outside thepatient) to deflect laterally by a desired amount to help steer, push,or twist instrument 200 to the desired location in the patient.

[0092] Coaxially inside tube 230 is tube 240. Tube 240 is longitudinallymovable relative to tube 230, and may be metal (e.g., stainless steel)hypotube, for example. Screw head 242 is mounted on the distal end oftube 240 and is threaded (as indicated at 244) on its distal conicalsurface. Tube 240 is rotatable (about the central longitudinal axis ofinstrument 200, either alone or with other elements) in order rotatehead 242 and thereby use threads 244 in engagement with the tissue ofthe aorta wall to help pull head 242 through that wall as will be morefully described below. Because tube 240 is hollow, it can be used forpassage of fluid or pressure into or out of the patient.

[0093] Coaxially inside tube 240 is longitudinal structure 250.Longitudinal structure 250 is longitudinally movable relative to tube240. Structure 250 may also be rotatable (about its longitudinal axis)relative to tube 240 and/or other elements. Structure 250 may be a wirewith a distal end portion 252 that is resiliently biased to deflectlaterally to one side. Wire portion 252 is kept relatively straight whenit is inside tube 240 as shown in FIG. 7a. But when wire portion 252 ispushed axially out the distal end of tube 240, it curves to one side asshown in FIG. 7b. As an alternative or addition to the above-describedresilient lateral deflection, the distal portion of structure 250 may bethreaded as shown at 254 in FIG. 7g to help structure 250 thread its waythrough the wall of aorta 30.

[0094] All of components 210, 220, 230, 240, and 250 are controlled fromoutside the patient's body (i.e., from region 202 in FIG. 5).

[0095] When the distal portion of catheter 210 is at the desiredlocation 34, proximal balloon 212 is inflated. Even when inflated,proximal balloon is not large enough to block aorta 30.

[0096] After proximal balloon 212 has been inflated, wire 250 is pusheddistally so that its distal portion emerges from the distal end of tube240 and penetrates the wall of aorta 30 at location 34. This anchors thedistal portion of instrument 200 to the aorta wall at the desiredlocation. Because of its operation to thus anchor instrument 200, wire250 is sometimes referred to as an anchor wire. The rotatability of wire250, as well as its resilient lateral deflection (FIG. 7b) and/orthreads 254 (FIG. 7g), may be used to help get the distal end of thewire to the desired location 34 and firmly into the aorta wall at thatlocation in order to achieve the desired anchoring of instrument 200.

[0097] When instrument 200 is sufficiently anchored by wire 250, tubes230 and 240 are moved in the distal direction relative to wire 250 SOthat screw head 242 begins to follow wire 250 into and through the aortawall. During this motion, at least tube 240 is rotated about itslongitudinal axis so that threads 244 help to pull head 242 into andthrough the aorta wall. The distal portion of tube 230 follows head 242through the aorta wall. If provided, threads 232 and rotation of tube230 may facilitate transfer of the aorta wall tissue from head 242 totube 230.

[0098] When tube 230 is through the aorta wall, sheath 220 is moveddistally relative to tube 230 so that a distal portion of sheath 220follows tube 230 through the aorta wall. If provided, the distal taper222 and/or threads 224 and rotation of sheath 220 help the distalportion of sheath 220 through the aorta wall. Then catheter 210 isadvanced distally relative to sheath 220 so that a distal portion ofcatheter 210 follows sheath 220 through the aorta wall. Again, thedistal taper 211 of catheter 210 (if provided) helps the distal portionof the catheter through the aorta wall. Inflated proximal balloon 212prevents more than just the portion of catheter 210 that is distal ofballoon 212 from passing through the aorta wall.

[0099] It should be mentioned that each time another, larger one ofelements 240, 230, 220, and 210 is pushed through the aorta wall, thepreviously extended elements can be and preferably are either heldstationary or pulled back proximally to prevent them from damaging bodytissues outside the aorta.

[0100] When the distal portion of catheter 210 is through the aortawall, distal balloon 214, which is now outside the aorta, is alsoinflated. The axial spacing between balloons 212 and 214 is preferablysmall enough so that the aorta wall is clamped between these twoballoons as shown in FIG. 8. For example, if balloons 212 and 214 wereinflated without the presence of the aorta wall, their appearance mightbe as shown in FIG. 8a. The close spacing of balloons 212 and 214, aswell as their resilient bias toward one another, helps to anchorcatheter 210 through the aorta wall and also to seal the aorta wallaround the catheter. Balloons 212 and 214 may be inflated by liquid orgas, and they may be specially coated to help improve the seal betweencatheter 210 and the aorta wall.

[0101] After the condition of catheter 210 shown in FIG. 8 has beenreached, all of components 220, 230, 240, and 250 can be withdrawn fromthe patient by pulling them out of catheter 210 in the proximaldirection.

[0102] The next step in the illustrative procedure being described is toinsert an elongated, steerable, endoscopic snare 300 lengthwise intocatheter 210. A simplified cross sectional view of an illustrativesteerable endoscopic snare is shown in FIG. 9. As shown in that FIG. ,snare 300 includes one or more sheath structures such as 310 a and 310 bthat are operable by the physician to steer the snare by curvilinearlydeflecting it laterally by a desired, variable amount. Within sheaths310 are such other components as (1) a fiber optic bundle 320 forconveying light from outside the patient to the distal end of snare 300in order to provide illumination beyond the distal end of the snare, (2)another fiber optic bundle 330 for conveying an image from beyond thedistal end of the snare back to optical and/or video equipment outsidethe patient and usable by the physician to see what is beyond the distalend of the snare, and (3) a snare sheath 340 with the actual snareinstrument 350 inside of it. Additional lumens such as 360 may beprovided for such purposes as introducing fluid that may help to clearthe distal ends of fiber optic bundles 320 and 330, for introducingfluid for irrigating and/or medicating the patient, for suctioning fluidfrom the patient, etc. It may not be necessary to provide a separatesnare sheath 340, but rather element 340 may merely be a lumen throughthe general structure 300 for snare instrument 350.

[0103] An illustrative embodiment of the distal portion of snareinstrument 350 is shown in FIG. 10. In this embodiment instrument 350includes a wire 352 with a snare loop 354 (also of wire) at its distalend. Loop 354 is closed when it is inside snare sheath or lumen 340.Loop 354 opens resiliently to the shape shown in FIG. 10 when it extendsdistally beyond the distal end of sheath or lumen 340.

[0104] In the alternative embodiment of instrument 350 shown in FIG.10a, snare loop 354 is mounted on the distal end of a fiber optic bundle352′. Fiber optic bundle 352′ may perform the functions described abovefor bundle 320 or bundle 330, thereby integrating those functions intoinstrument portion 350.

[0105] In the further alternative embodiment of instrument 350 shown inFIG. 10b, snare loop 354 is mounted on the distal end of a tube 352″,which can be used to deliver other types of instrumentation to thevicinity of snare loop 354. For example, tube 352″ may be metal (e.g.,stainless steel) hypotube, and the other instrumentation delivered viathat tube may be a tissue cutter for use in cooperation with snare loop354 to perform a biopsy.

[0106] In the still further alternative embodiment shown in FIG. 10c,snare loop 354 is part of one continuous length of wire 352 a. Apossible advantage of the embodiment shown in FIG. 10c is that itpermits snare loop 354 to be variable in size, determined by how much ofwire 352 a is extended from the distal end of lumen 340.

[0107] As shown in FIG. 11, the distal portion of steerable endoscopicsnare 300 is extended distally beyond the distal end of catheter 210 andsteered by the physician until it is adjacent to the exterior ofcoronary artery portion 24.

[0108] The next step in the illustrative procedure being described ispreferably to deploy snare loop 354 by extending it distally from thedistal end of structure 300 as shown in FIG. 12. Alternatively, thisstep could be performed somewhat later.

[0109] The next step (also shown in FIG. 12) is to inflate balloon 132to push tube 120 against the opposite side wall of coronary artery 20 atlocation 24. Then stylet wire 150 is moved in the distal direction asshown in FIG. 12 so that its distal tip 152 passes through the wall ofthe coronary artery. As was mentioned earlier, the distal end of thestylet wire lumen in tube 120 is shaped to help guide stylet wire 150through the coronary artery wall. After stylet wire 150 is through thecoronary artery wall, balloon 132 can be deflated. Balloon 132 may be aperfusion balloon which allows continued blood flow along artery 20 evenwhile the balloon is inflated.

[0110] It may not be necessary to have a balloon 132 directly oppositethe outlet for wire 150. For example, FIG. 12a shows an alternativeembodiment in which a perfusion balloon 132′ is provided on tube 120proximally of the outlet for wire 150. Balloon 132′ is inflated when itis desired to stabilize the location of tube 120 in coronary artery 20(e.g., while the distal portion of wire 150 is being pushed out throughthe coronary artery wall). Another possibility is for a balloon like132′ to be near the distal end of a balloon catheter from which tube 120extends distally. Still another possibility may be to omit balloons like132 and 132′ entirely. If a balloon 132 or 132′ is provided, it may notbe necessary for it to be a perfusion balloon.

[0111] When the distal portion of stylet wire 150 is outside coronaryartery 20, the next step is to ensure that the distal portion of thewire passes through snare loop 354 as shown in FIG. 12 or FIG. 12a. Thismay be facilitated by continued use of the visual observation andsteering capabilities of snare 300. An especially preferred technique isto deploy snare loop 354 so that it is next to coronary artery section24. Then when stylet wire 150 emerges from the coronary artery at 24, itimmediately passes through snare loop 354 with no further manipulationbeing required.

[0112] Once wire 150 is through snare loop 354, snare sheath or lumen340 is moved distally relative to the snare loop. This causes snare loop354 to close down on wire 150. Snare sheath or lumen 340 also tends totrap the distal portion of wire 150 and to fold that wire portion backon itself inside sheath or lumen 340 as shown in FIG. 13.

[0113] When the condition shown in FIG. 13 is achieved, longitudinalstructures 150 and 350 are securely interengaged inside snare sheath orlumen 340. The next step is to pull wire 352 in the proximal directionall the way out of the patient at location 202 (FIG. 5). Because of theinterengagement between wires 150 and 352, withdrawing wire 352 pulls asmuch additional wire 150 into the patient from external location 102(FIG. 1). When wire 352 has been completely removed from the patient,there is then one continuous wire 150 from outside the patient at 102,through the patient, to outside the patient at 202. Wire 150 can now bemoved in either longitudinal direction through the patient. This wire oranother wire could be used to help pull various apparatus into thepatient via the tube or tubes through which the wire passes.

[0114] After one continuous wire 150 has been established through thepatient as described above, steerable endoscopic snare 300 may bewithdrawn from the patient by pulling it proximally out of catheter 210.The condition of the apparatus inside the patient is now as shown inFIG. 14. Note that the presence of fixed outlets for the wire from thedistal portion of tube 120 and the distal end of catheter 210 preventswire 150 from cutting tissues 20 and 30 when the wire is pulled ineither longitudinal direction. The portion of wire 150 extending throughthe interior of the patient between elements 120 and 210 may haveradiologic markers 154 equally spaced along its length. These can beviewed radiologically by the physician to determine the distance betweenregions 24 and 34 via wire 150. This helps the physician select thecorrect length of graft needed between regions 24 and 34.

[0115] The next phase of the illustrative procedure being described isto install a new length of tubing between regions 24 and 34. The newlength of tubing may be either an artificial graft, natural body organtubing harvested from the patient's body, or a combination of artificialand natural tubing (e.g., natural tubing coaxially inside artificialtubing). In the following discussion it is assumed that the new tubingis to be natural tubing (e.g., a length of the patient's saphenous veinthat has been harvested for this purpose) inside an artificial conduit.When such a combination of natural and artificial conduits is used, bothconduits can be delivered and installed simultaneously, or the outerartificial conduit can be delivered and installed first, and then theinner natural conduit can be delivered and installed. The followingdiscussion initially assumes that the latter technique is employed.

[0116] In accordance with the above-stated assumptions, the next step inthe procedure is to use catheter 210 and wire 150 to deliver anartificial conduit so that it extends between regions 24 and 34. Thedistal portion of an illustrative assembly 400 for doing this is shownin FIG. 15. (Several alternative constructions of this portion of theapparatus are shown in later FIGS. and described below.)

[0117] As shown in FIG. 15 assembly 400 includes a threaded, conical,distal tip 412 mounted on a tubular member 410 (e.g., metal hypotube)through which wire 150 can freely pass. Additional details regardingvarious possible constructions of tip 412 are provided later withreference to FIGS. 15a-15 g, but it should be mentioned here that inthis embodiment tip 412 is selectively collapsible to facilitate itswithdrawal from the patient after it has served its purpose. Anothertubular member 420 is disposed concentrically around tubular member 410.An inflatable balloon 422 is mounted on the distal end of tubular member420. Tubular member 420 includes an axially extending lumen (not shownin FIG. 15) for use in selectively inflating and deflating balloon 422.Balloon 422 is shown deflated in FIG. 15.

[0118] Coaxially around tubular member 420 is an artificial graftconduit 430. An illustrative embodiment of a suitable conduit 430 isshown in FIG. 16 and includes a tube formed of a frame 432 of a firsthighly elastic material (such as nitinol) with a covering 434 of asecond highly elastic material (e.g., a rubber-like material such assilicone) substantially filling the apertures in the frame. Additionalinformation regarding this possible embodiment of conduit 430 and otherartificial graft structures in accordance with the invention is providedin later portions of this specification. Here it will suffice to saythat this structure is extremely elastic, flexible, pliable, andresilient. For example, it can be stretched to a small fraction of itsoriginal diameter, and it thereafter returns by itself to its originalsize and shape without damage or permanent deformation of any kind. Inaddition, this structure is distensible so that it may pulsate very muchlike natural circulatory system tubing in response to pressure waves inthe blood flow. This helps keep the conduit open, especially if it isused by itself as the final graft conduit. At its distal end, extensionsof frame 432 are flared out to form resilient hooks or barbs 436, thepurpose of which will become apparent as the description proceeds. Nearthe proximal end of conduit 430 two axially spaced resilient flaps 438 aand 438 b with barbs 439 are provided. The purpose and operation ofelements 438 and 439 will also become apparent as the descriptionproceeds.

[0119] In assembly 400 (see again FIG. 15, and also FIG. 17), barbs 436and flaps 438 are compressed radially inwardly and confined withinconduit delivery tube 440, which coaxially surrounds conduit 430.Indeed, conduit 430 may be somewhat circumferentially compressed by tube440.

[0120] The portion of assembly 440 at which the proximal end of conduit430 is located is shown in FIG. 17. There it will be seen how flaps 438are confined within conduit delivery tube 440. FIG. 17 also shows howtubes 410, 420, and 440 extend proximally (to the right as viewed inFIG. 17) from the proximal end of conduit 430 so that the physician canremotely control the distal portion of assembly 400 from outside thepatient.

[0121] To install artificial graft conduit 430 in the patient betweenregions 24 and 34, assembly 400 is fed into the patient along wire 150through catheter 210. When tip 412 reaches coronary artery portion 24,tip 412 is threaded into and through the coronary artery wall byrotating tube 410 and therefore tip 412. (Tube 120 may be pulled backslightly at this time to make sure that it does not obstruct tip 412.)The passage of tip 412 through the coronary artery wall opens up theaperture in that wall. After tip 412 passes through the artery wall,that wall seals itself against the outside of the distal portion ofconduit delivery tube 440 as shown in FIG. 18.

[0122] The next step is to push tube 410 and tip 412 distally relativeto delivery tube 440, which is held stationary. Conduit 430 is initiallymoved distally with components 410 and 412. This may be done byinflating balloon 422 SO that it engages conduit 430, and then movingtube 420 distally with components 410 and 412. Distal motion of conduit430 moves barbs 436 beyond the distal end of delivery tube 440, therebyallowing the barbs to spring out inside coronary artery 20 as shown inFIG. 19. This prevents the distal end of conduit 430 from being pulledproximally out of the coronary artery. If balloon 422 was inflatedduring this phase of the procedure, it may be deflated before beginningthe next phase.

[0123] The next step is to pull delivery tube 440 back slightly so thatit is withdrawn from coronary artery 20. Then tube 420 is moved distallyso that balloon 422 is radially inside the annulus of barbs 436. Balloon442 is then inflated to ensure that barbs 436 are firmly set in coronaryartery 20. Conditions are now as shown in FIG. 20. Cross sections ofballoon 422 may be L-shaped when inflated (one leg of the L extendingparallel to the longitudinal axis of conduit 430, and the other leg ofthe L extending radially outward from that longitudinal axis immediatelydistal of barbs 436). This may further help to ensure that barbs 436fully engage the wall of coronary artery 20.

[0124] The next step is to deflate balloon 422. Then delivery tube 440is withdrawn proximally until flap 438 a (but not flap 438 b) is distalof the distal end of the delivery tube. This allows flap 438 a to springradially out as shown in FIG. 21. Tube 420 is then withdrawn untilballoon 422 is just distal of flap 438 a. Then balloon 422 is inflated,producing the condition shown in FIG. 21.

[0125] The next steps are (1) to deflate distal balloon 214, (2) toproximally withdraw catheter 210 a short way, (3) to proximally withdrawtube 420 to press flap 438 a against the outer surface of the aortawall, and (4) to proximally withdraw delivery tube 440 by the amountrequired to allow flap 438 b to spring out against the interior ofcatheter 210, all as shown in FIG. 22. As a result of theabove-described proximal withdrawal of tube 420, the barbs 439 on flap438 a are urged to enter the aorta wall tissue to help maintainengagement between flap 438 a and the wall of the aorta. Inflatedballoon 422 helps to set barbs 439 in the tissue when tube 420 is tuggedproximally.

[0126] The next step is to insert the distal portion of delivery tube440 into the proximal end of conduit 430 as shown in FIG. 22a. Thedistal end of conduit 440 may be inserted all the way to the proximalend of balloon 422 (see FIG. 23 for a depiction of this). A purpose ofthis step is to subsequently help control the rate at which blood isallowed to begin to flow through conduit 430.

[0127] The next step is to proximally withdraw catheter 210 by theamount required to release flap 438 b to spring out against the interiorof the wall of aorta 30 as shown in FIG. 22b. Catheter 210 may besubsequently pushed back against flap 438 b as shown in FIG. 23 to helpsecurely engage that flap against the aorta wall.

[0128] Artificial graft conduit 430 is now fully established betweenaorta region 34 and coronary artery region 24. The next steps aretherefore to deflate balloon 422 and proximally withdraw tube 420, tocollapse tip 412 and proximally withdraw tube 410, and to proximallywithdraw delivery tube 440. The proximal end of conduit 430 is now asshown in FIG. 24. As possible alternatives to what is shown in FIG. 24,the distal end of catheter 210 could be left pressed up against proximalflap 438 b and/or the distal portion of delivery tube 440 could be leftinside the proximal portion of conduit 430. If the latter possibility isemployed, then delivery of the natural graft conduit (described below)can be through tube 440.

[0129] Several illustrative embodiments of collapsible tips 412 areshown in FIGS. 15a-15 g. In the first embodiment (shown in FIGS. 15a-15c) a frame of wire struts 412 a extends radially out and proximally backfrom the distal end of hypotube 410 (see especially FIG. 15a). Thisframe is covered with a somewhat elastic polymer cover 412 b (FIG. 15b)which is provided with threads as indicated at 412 c. For example,threads 412 c may be made of one or more spirals of nitinol wire orother metal. When it is desired to collapse tip 412, another hypotube410 a (which is disposed around hypotube 410) is shifted distallyrelative to hypotube 410 to invert and collapse tip 412 as shown in FIG.15c.

[0130] In the alternative embodiment shown in FIGS. 15d and 15 e, tip412 has a central main portion 412 e attached to hypotube 410. Aroundthe proximal portion of main portion 412 e are a plurality of triangularshaped portions 412 f, each of which is connected to main portion 412 eby a hinge 412 g. The outer surface of the tip is threaded as indicatedat 412h. For example, in this embodiment tip 412 may be made of aplastic polymer material, and hinges 412 g may be so-called “living”hinges between the various masses of the polymer. As soon as triangularportions 412 f meet any resistance as tip 412 is withdrawn proximally,they pivot about their hinges 412 g to the positions shown in FIG. 15e,thereby greatly reducing the circumferential size of the tip.

[0131] In the further alternative embodiment shown in FIGS. 15f and 15g, metal struts 412 j are attached to the distal end of hypotube 410 sothat they extend radially out and proximally back. Although not shown inFIGS. 15f and 15 g, struts 412 j are covered with a cover and threadslike the cover 412 b and threads 412 c shown in FIG. 15b and describedabove. A wire 412 k connects a proximal portion of each strut 412 j,through an aperture in hypotube 410, to the distal end of anotherhypotube 410 b which is disposed inside hypotube 410. When wires 412 kare relaxed as shown in FIG. 15f, struts 412 j extend radially outbeyond the circumference of delivery tube 440. When it is desired tocollapse tip 412, hypotube 410 b is pulled back proximally relative tohypotube 410 as shown in FIG. 15g. This causes wires 412 k to pullstruts 412 j in so that the outer circumference of tip 412 is muchsmaller than the circumference of delivery tube 440.

[0132] Again, it should be mentioned that the use of a threaded,collapsible tip 412 as described above is only one of severalpossibilities. Other alternatives are discussed below after completionof the discussion of the illustrative procedure which is being describedand which will now be further considered with reference to FIG. 25 andsubsequent FIGS.

[0133] As has been mentioned, the illustrative procedure being describedassumes that natural body conduit (e.g. a length of the patient'ssaphenous vein that has been harvested for this purpose) is installedinside artificial conduit 430 after installation of the latter conduit.An illustrative assembly 500 for delivering a length of natural bodyconduit to installed conduit 430 is shown in FIG. 25.

[0134] As shown in FIG. 25, assembly 500 includes a tube 510 disposedaround wire 150 so that tube 510 is freely movable in either directionalong wire 150. Tube 510 has an inflatable annular balloon 512 a nearits distal end and another inflatable annular balloon 512 b spaced inthe proximal direction from balloon 512 a. Tube 510 includes separateinflation lumens (not shown) for each of balloons 512 so that theballoons can be separately inflated and deflated. An annular collarstructure or ring 520 a is disposed concentrically around balloon 512 a,and a similar annular collar structure or ring 520 b is disposedconcentrically around balloon 512 b. Balloons 512 may be partlyinflated. Each of rings 520 may have radially outwardly extending barbs522. A length of natural body conduit 530 (e.g., saphenous vein asmentioned earlier) extends from ring 520 a to ring 520 b around theintervening portion of tube 510. Barbs 522 may extend through theportions of conduit 530 that axially overlap rings 520. A delivery tube540 is disposed around conduit 530. In use, tubes 510 and 540 extendproximally (to the right as viewed in FIG. 25) out of the patient topermit the physician to remotely control the distal portion of assembly500.

[0135] Although not shown in FIG. 25, assembly 500 may include a springcoil (similar to coil 450 in FIG. 36) extending between rings 520 insideof conduit 530 to help hold conduit 530 open and out against deliverytube 540 or subsequently out against conduit 430. Instead of balloons512 being both in the same tube 510, balloon 512 a may be on arelatively small first tube, while balloon 512 b is on a larger secondtube that concentrically surrounds the proximal portion of the firsttube. The first and second tubes are axially movable relative to oneanother, thereby allowing the distance between balloons 512 to beadjusted for grafts 530 of different lengths.

[0136] Assembly 500 is employed by placing it on wire 150 leading intocatheter 210. Assembly 500 is then advanced distally along wire 150through catheter 210 and then into conduit 430 until the distal end ofconduit 530 is adjacent the distal end of conduit 430 and the proximalend of conduit 530 is adjacent the proximal end of conduit 430. Thecondition of the apparatus at the distal end of assembly 500 is now asshown in FIG. 26. The condition of the apparatus at the proximal end ofconduit 530 is as shown in FIG. 28.

[0137] The next step is to proximally withdraw delivery tube 540 so thatthe distal portion of conduit 530 and distal barbed ring 520 a are nolonger inside the distal portion of delivery tube 540. Then distalballoon 512 a is inflated to circumferentially expand ring 520 a and toset barbs 522 through conduit 530 into the surrounding portion ofconduit 430 and coronary artery wall portion 24. This provides acompleted anastomosis of the distal end of conduit 530 to coronaryartery 20. FIG. 27 shows the condition of the apparatus at this stage inthe procedure.

[0138] The next step is to continue to proximally withdraw delivery tube540 until the proximal end of conduit 530 and proximal ring 520 b are nolonger inside tube 540 (see FIG. 29). Then proximal balloon 512 b isinflated to circumferentially expand ring 520 b and thereby set barbs522 through conduit 530 into the surrounding portion of conduit 430 andaorta wall portion 34 (see FIG. 30). This provides a completedanastomosis of the proximal end of conduit 530 to aorta 30.

[0139] The next step is to deflate balloons 512 a and 512 b andproximally withdraw tube 510 and delivery tube 540 from the patient viacatheter 210. Then wire 150 is withdrawn from the patient, either bypulling it proximally from catheter 210 or by pulling it proximally fromelements 110 and 120. Lastly, elements 110, 120, and 210 are allproximally withdrawn from the patient to conclude the procedure. Thebypass that is left in the patient is as shown in FIG. 31. This bypassextends from aorta 30 at location 34 to coronary artery 20 at location24. The bypass includes natural body conduit 530 inside artificial graftconduit 430. One end of the bypass is anchored and anastomosed tocoronary artery 20 by barbs 436 and ring 520 a. The other end of thebypass is anchored and anastomosed to aorta 30 by flaps 438 and ring 520b.

[0140] The particular uses of the invention that have been described indetail above are only illustrative of many possible uses of theinvention. Other examples include same-vessel bypasses in the coronaryarea and vessel-to-vessel and same-vessel bypasses in other portions ofthe circulatory system (including neurological areas, renal areas,urological areas, gynecological areas, and peripheral areas generally).A same-vessel bypass is a bypass that extends from one portion of avessel to another axially spaced portion of the same vessel. In FIG. 32,bypass 620 is a same-vessel bypass around a narrowing 612 in vessel 610.For ease of comparison to previously described embodiments, the variouscomponents of bypass 620 are identified using the same reference numbersthat are used for similar elements in FIG. 31. The invention is alsoapplicable to procedures similar to any of those mentioned above, butfor non-circulatory systems such as urological tubing.

[0141] It has been mentioned that the collapsible tip structures shown,for example, in FIGS. 15-15 g are illustrative of only one of severalpossible approaches to providing a structure that can penetrate the wallof coronary artery 20 from outside the artery. Another example of asuitable structure is shown in FIG. 33. To facilitate comparison to FIG.15, FIG. 33 uses reference numbers with primes for elements that aregenerally similar to elements identified by the corresponding unprimedreference numbers in FIG. 15.

[0142] In the embodiment shown in FIG. 33 distal tip 412′ has externalthreads 414 for helping to grip and dilate tissue such as the wall ofcoronary artery 20 as tip 412′ is rotated about wire 150 by rotation ofproximally extending tubular shaft 410′. Threads 414 continue as threads442 on the exterior of the distal portion of tube 440′. Threads 414 alsothreadedly engage with threads 444 on the interior of the distal portionof tube 440′. Thus when both of structures 410′ and 440′ are rotatedtogether, threads 414 and 442 tend to pull tip 412′ and then the distalportion of tube 440′ into and through the wall of coronary artery 20. Inthe course of this, threads 412′ transfer the tissue to threads 442.Thereafter, structure 410′ can be removed from structure 440′ byrotating structure 410′ in the direction relative to structure 440′ thatcauses threads 414 and 444 to cooperate to shift tip 412′ proximallyrelative to structure 440′. When tip 412′ has thus shifted proximallybeyond threads 444, elements 410′ and 412′ can be pulled proximally outof the patient. Tube 440′, which remains in place through the coronaryartery wall, can thereafter be used as a guide tube for delivery of agraft structure (such as 430 (FIGS. 15-17)) and associatedinstrumentation (such as structure 420 (e.g., FIGS. 15 and 17)) to theoperative site.

[0143] Another illustrative alternative embodiment of some of theinstrumentation shown in FIG. 15 is shown in FIGS. 34 and 35. Onceagain, to facilitate comparison to FIG. 15, FIGS. 34 and 35 usereference numbers with primes for elements that are generally similar toelements identified by the corresponding unprimed reference numbers inFIG. 15. In the embodiment shown in FIGS. 34 and 35 barbs 436′ areconnected to the distal end of a serpentine ring 439 which is connectedin turn to the distal end of frame 432′. Barbs 436′ are initially heldin the form of a distally pointed cone by yieldable bands 437 a, 437 b,437 c, and 437 d. As elsewhere along graft conduit 430′, the spacesbetween barbs 436′ are substantially filled by a highly elastic materialsuch as silicone rubber. Bands 437 may be made of a polymeric or othersuitable yieldable material. Alternatively, bands 437 could beserpentine metal members that yield by becoming straighter. Bands 437are initially strong enough to prevent barbs 436′ from flaring radiallyoutward from conduit 430′ as the barbs are resiliently biased to do.However, bands 437 can be made to yield by inflating balloon 422′ (onthe distal end of tube 420′) inside the annulus of barbs 436′.

[0144] Barbs 436′ can be forced through tissue such as the wall ofcoronary artery 20 in their initial cone shape. Sufficient pushing forcecan be applied to the cone of barbs 436′ in any of several ways. Forexample, tube 420′ may be metal (e.g., stainless steel) hypotube whichcan transmit pushing force to the cone of barbs 436′ by inflatingballoon 422′ to trap the base of the cone between balloon 422′ and tube440. Additional pushing force may then also be applied via tube 440itself.

[0145] When a sufficient portion of the height of the cone of barbs 436′is through the coronary artery wall, balloon 422′ is inflated inside thecone as shown in FIG. 35 to cause bands 437 to yield. This allows barbs436′ to flare radially outward inside the coronary artery, therebyanchoring the distal end of conduit 430′ to the artery. Bands 437 may bemade progressively weaker in the distal direction to facilitate promptyielding of distal bands such as 437 a and 437 b in response torelatively little inflation of balloon 422′, whereas more proximal bandssuch as 437 c and 437 d do not yield until somewhat later in response togreater inflation of balloon 422′. This progression of yielding may helpensure that the annulus of barbs flares out in the desired trumpet-bellshape inside the coronary artery.

[0146]FIGS. 36 and 37 illustrate another possible use of a conestructure like that shown in FIGS. 34 and 35, as well as illustratingother possible aspects of the invention. These FIGS. illustrate astructure that can be used to deliver an artificial graft conduit, or anatural graft conduit, or both an artificial graft conduit and a naturalgraft conduit simultaneously (e.g., with the natural conduit coaxiallyinside the artificial conduit). In the particular case shown in FIGS. 36and 37 it is assumed that only natural graft conduit is being delivered,but it will be readily apparent that artificial graft conduit could besubstituted for or added outside the natural graft conduit.

[0147] In the embodiment shown in FIGS. 36 and 37 the cone of barbs 436′is mounted on the distal end of a highly elastic coil spring 450. Theproximal end of coil 450 is attached to ring 460. The cone of barbs 436′is provided with additional, relatively short, radially outwardlyprojecting barbs 436″ near the proximal base of the cone. As shown inFIG. 37, barbs 436″ extend into and/or through the distal portion of alength of graft tubing 530, which (as has been mentioned) is assumed inthis case to be natural body organ tubing such as saphenous vein. Ring460 is similarly provided with radially outwardly extending barbs 462which extend into and/or through the proximal portion of graft conduit530. Ring 460 also includes resilient radially outwardly extendingannular flaps 438 a and 438 b with barbs 439, all similar tocorrespondingly numbered elements in FIG. 16. Spring 450, which isinside conduit 530 between the cone of barbs 436′ and ring 460, helps tosupport and hold open the graft conduit. Structure 420′ (similar tostructure 4201 in FIGS. 34 and 35 and including balloon 422′ as shown inthose FIGS. ) is disposed around wire 150 inside structures 436′, 450,460, and 530. Delivery tube 440 is disposed around conduit 530.

[0148] The embodiment shown in FIGS. 36 and 37 illustrates a structurewhich can be used to deliver and install natural body organ conduitwithout any full length artificial graft conduit being used. In a mannersimilar to what is shown in FIGS. 34 and 35, the structure shown in FIG.37 is delivered to the operative site via wire 150. The cone of barbs436′ is forced through the wall of coronary artery 20 and then flaredradially outward inside the coronary artery to anchor the distal end ofthe graft conduit to that artery. The distal end of delivery tube 440 ispulled back as needed to aid in attachment of the distal end of thegraft structure. Attachment of the proximal end of the graft structureto the wall of aorta 30 is performed similarly to what is shown in FIGS.21-24. Accordingly, with distal flap 438 a just outside the wall ofaorta 30, delivery tube 440 is pulled back proximally to expose thatflap. Flap 438 a is thereby released to spring out and engage the outersurface of the aorta wall. After that has occurred, proximal flap 438 bis adjacent the inner surface of the aorta wall. Tube 440 is pulled backproximally even farther to expose flap 438 b so that it can spring outand engage the inner surface of the aorta wall. Natural body organ graft530 is now fully installed in the patient. Structures 436′, 450, and 460remain in place in the patient to help anchor the ends of graft conduit530 and to help hold open the medial portion of that conduit.

[0149] In embodiments like FIGS. 36 and 37, coil 450 is optional. Ifcoil 450 is used, its ends may or may not be attached to structures 436and/or 460.

[0150] A coil like coil 450 can be used in other embodiments of theinvention. For example, a coil like 450 could be used between rings 520a and 520 b in embodiments like that shown in FIG. 25 to help hold opengraft conduit 530 in that embodiment.

[0151] Still another illustrative alternative embodiment of some of theinstrumentation shown in FIG. 15 is shown in FIG. 38. To facilitatecomparison to FIG. 15, FIG. 38 uses reference numbers with double primesfor elements that are generally similar to elements identified by thecorresponding unprimed reference numbers in FIG. 15. In the embodimentshown in FIG. 38, the distal end of artificial graft conduit 430″ isattached to expandable ring 430 a. Elongated barbs 436″ extend distallyfrom the distal end of ring 430 a. The distal ends of barbs 436″ areturned back in the proximal direction and extend just far enough intothe distal end of tube 420″ to be releasably retained by that tube.Barbs 436″ are resiliently biased to extend radially outward from ring430 a, but are initially restrained from doing so by the presence oftheir distal end portions in the distal end of tube 420″. Thus barbs436″ initially form a distally pointing cone that can be pushed throughtissue such as the wall of coronary artery 20 in the same manner thathas been described above in connection with FIGS. 34-37. Structure 420″,which may be metal (e.g., stainless steel) hypotube with an inflatableannular balloon 422″ near its distal end, may be used to help push thecone through the tissue.

[0152] After the distal portion of the cone of barbs 436″ has beenpushed through the wall of coronary artery 20, tube 420″ is shiftedproximally relative to the barbs to release the distal end portions ofthe barbs. This allows barbs 436″ to spring radially outward from ring430 a inside coronary artery 20, thereby anchoring the distal end of thegraft conduit in the coronary artery. Ring 430 a can then becircumferentially expanded to increase the size of the connectionbetween coronary artery 20 and the distal portion of the graft conduit.If desired, each of barbs 436″ may be twisted 1800 as shown in FIG. 39before it enters the distal end of tube 420″. This promotes turning ofthe extreme distal end portions of the barbs toward the coronary arterywall when the barbs are released from tube 420″.

[0153] Ring 430 a and barbs 436″ may be made of any suitable materialsuch as any 300-series stainless steel (e.g., 316L stainless steel).Another material that may be suitable for barbs 436″ is nitinol. As inpreviously described embodiments, the elastic cover 434 that forms partof conduit 430″ preferably extends to regions 430 a and 436″.

[0154] A preferred artificial graft (such as conduit 430 in FIG. 16) inaccordance with this invention includes an open frame structure (such as432 in FIG. 16). This frame structure may have any desired shape such asa tube, a flat or contoured sheet, etc. The frame structure may beformed in any suitable way such as by cutting apertures in an initiallyimperforate structure; forming a mesh of strands of frame material;braiding, knitting, weaving, or felting together strands of framematerial; etc. The frame material is preferably an elastic material.Preferred materials are metal, although polymeric materials may also beused. The presently most preferred material is nitinol, and thepresently most preferred structure for the frame of a tubular graft is abraid of nitinol wires.

[0155] The above-described graft frame is preferably covered with acovering of elastic rubber-like material which substantially fills theapertures in the frame as at 434 in FIG. 16. The covering may be insidethe frame structure, outside the frame structure, or both inside andoutside the frame structure. Preferred rubber-like materials for thecovering are polymeric materials, especially polymeric rubber materials.The presently most preferred rubber-like material is silicone. Examplesof other suitable rubber-like materials are stretchable urethane,stretchable PTFE, natural rubber, and the like. For some applications itmay be desirable to make the covering porous. Other applications may notbenefit from such porosity. Thus the covering can be made either porousor non-porous as desired.

[0156] The graft structure may include one or more coatings over theabove-described covering. In the case of a tubular graft the coating(s)may be inside the tube, outside the tube, or both inside and outside thetube. Possible coating materials include bio-compatible materials and/ordrugs. Examples include hydrophylic polymers such as hydrophylicpolyurethane (to create a lubricious surface), parylene (a polymercommonly used to coat pacemakers), PTFE (which may be deposited from aPTFE vapor using a process that is sometimes called vapor transport),the drug Heparin (a common anti-coagulant), collagen, human cellseeding, etc. One purpose of such a coating may be to give the coatedsurface a very high degree of bio-compatibility and/or a very highdegree of smoothness.

[0157] The graft structure may or not include hooks, barbs, flaps, orother similar structures for such purposes as helping to anchor thegraft in the body, provide anastomoses between the graft and existingbody tubing, etc. Several examples of such structures are shown anddescribed elsewhere in this specification. If provided, such hooks,barbs, flaps, and the like may be extensions of the frame structure ormay be molded with or otherwise added to the frame or covering.

[0158] The most preferred grafts of this invention (e.g., those with anitinol frame and silicone covering) are highly elastic. The elasticnature of these graft structures allows them to be deployed lessinvasively (e.g., intravascularly or at least percutaneously). Thisavoids or reduces the need for surgical implantation. For example, atubular graft of this construction can be stretched to several times itsrelaxed length, which greatly reduces its diameter. This facilitatesintravascular delivery of the graft. When released from the deliveryapparatus, the graft automatically returns to its relaxed length anddiameter, with no ill-effects of any kind from its previous deformation.If installed in the circulatory system, the graft is so flexible andelastic that it pulsates in response to pressure waves or pulses in theblood flow. This distensibility of the graft may help prevent bloodclots. Coatings that are used on the graft are preferably similarlydistensible.

[0159] In the grafts of this invention that are made with a braidednitinol wire frame and a silicone covering, the preferred wire diameteris in the range from about 0.0005 to about 0.01 inches. An especiallypreferred wire diameter is about 0.002 inches. The preferred siliconecovering thickness is in the range from about 0.00025 to about 0.1inches. Two covering layers may be used: one inside and one outside theframe structure. If the covering is made porous, the preferred pore sizeis in the range from about 1 to about 500 microns. An especiallypreferred pore size is about 30 microns. The preferred covering porosityis in the range from about 50% to about 95%. In other words, from about50% to about 95% of the volume of the covering is pore space. If anycoatings are applied to the graft, they are preferably thinner than thecovering.

[0160] For the preferred grafts of this invention, a preferredmanufacturing process in accordance with the invention includes placingor forming the frame structure of the graft on a form (e.g., a rod-likemandrel or tube in the case of the frame for a tubular graft). The form(e.g., mandrel) may be coated with a release agent such as polyvinylalcohol. The covering is then applied to the frame or the form. Thecovering is cured, and the frame and covering are removed from the form.Any release agent that remains on the graft is removed. For example, ifthe release agent is polyvinyl alcohol, it may be removed by boiling thegraft in water. If a covering is desired on the inside of the graft, alayer of the covering material may be applied to the form before theframe structure is placed or formed on the form. The form may beprovided with a very smooth surface to give the finished graft acorrespondingly smooth surface. For example, a very smooth mandrel maybe used to give the inside of a tubular graft a very smooth surface.

[0161] If one or more coatings are desired on the graft, the coating maybe done at any suitable time. For example, the coating may be done afterthe graft has been removed from the form. The coating or coatings may beapplied using any suitable technique such as dipping, electrostaticspraying, vapor transport, in vitro cell reproduction, etc.

[0162] A preferred method in accordance with the invention for makingthe graft covering porous is to mix particles of another material withthe covering material before applying the covering material to theframe. The particulate material is selected as one which is stable or atleast relatively stable during curing of the covering on the frame, butwhich can then be removed from the cured covering to leave the coveringwith the desired porosity. For example, the particulate material may bea salt such as ammonium carbonate, which is relatively stable attemperatures substantially below about 78° C., but which vaporizesrelatively rapidly at an elevated temperature (i.e., about 78° C.) thatis not harmful to the cured coating material. Any other particulatematerial that can be removed by vaporization or solution can be used.For example, the particulate material may be removed by dissolving inwater or another solvent, by exposure to air or another vaporizationmedium, by heat, by vacuum, or by any other suitable means.

[0163] Porosity of the covering is believed to be beneficial forcirculatory system grafts. It may promote growth of a cell structure onthe inside wall of the graft. And in all uses, porosity may promotebetter adherence of the above-mentioned coatings to the graft.

[0164] It will be understood that the foregoing is only illustrative ofthe principles of the invention, and that various modifications can bemade by those skilled in the art without departing from the scope andspirit of the invention. For example, the order of some steps in theprocedures that have been described are not critical and can be changedif desired. The manner in which radiologic elements and techniques areused for observation of the apparatus inside the patient may vary. Forexample, radiologic fluids may be injected into the patient throughvarious lumens in the apparatus to help monitor the location of variousapparatus components in the patient, and/or radiologic markers (of whichthe above-described markers such as 112, 124, and 154 are examples) maybe provided anywhere on the apparatus that may be helpful to thephysician.

The invention claimed is:
 1. A guided punch, comprising: a sharp,extendible guide wire; and a hollow punch mechanism adapted to ride onthe guide wire, wherein said guide wire is adapted to extend from saidpunch.
 2. A punch according to claim 1, wherein said punch is a rotatingpunch.
 3. A punch according to claim 1, wherein said punch is an axiallymoving punch.
 4. An anastomotic connector, comprising: a cylinder-likebody; and at least one set of spikes, coupled to said body by twistingjoints.
 5. A connector according to claim 4, wherein said twistingjoints comprise at least one torsion bar.
 6. A connector according toclaim 4, wherein said twisting joints comprise at least one bend area.7. A medical graft delivery system, comprising: a tubular element fordelivering a graft through a bore thereof and having a delivery end,said end being prone to distortion; and at least one collar removablyencircling said delivery end, which collar prevents said distortion. 8.A system according to claim 7, wherein said tube comprises weakenedportions at or adjacent said delivery end.
 9. A system according toclaim 7, comprising an anastomotic connector preloaded in said deliveryend and applying outward forces against said end.
 10. A system accordingto any of claims 7-9, wherein said at least one collar comprises atleast two collars.
 11. A method of sealing an opening between two bloodconduit lips, comprising: providing a clip; first retracting a first lipinto said clip; and second retracting a second lip into said clip.
 12. Amethod according to claim 11, comprising closing said clip to seal saidopening.
 13. A method according to claim 12, wherein closing comprisesreleasing said clip to selfdeform.
 14. A method according to claim 12,wherein closing comprises plastically deforming said clip.
 15. A methodaccording to any of claims 11-14, wherein said two lips are lips ofdifferent conduits.
 16. A method according to any of claims 11-14,wherein at least one of the conduits comprises a blood vessel.
 17. Areducing profile anastomotic connector, comprising: a ring section; aspikes section comprises a plurality of spikes, wherein said spikessection defines a collapsing portion, for axial collapsing of saidspikes section.
 18. A connector according to claim 17, wherein saidcollapsing portion buckles.
 19. A connector according to claim 17,wherein said collapsing portion twists.
 20. A connector according toclaim 17, wherein said collapsing portion folds out.
 21. A connectoraccording to any of claims 17-20, wherein said collapsing portionselfdeforms.
 22. A connector according to any of claims 17-20, whereinsaid collapsing portion plastically deforms.